1. Technical Field
The present disclosure relates to a method of local dimming, a backlight assembly for performing the method, and a display apparatus having the backlight assembly. More specifically, the present disclosure relates to a method of local dimming that is capable of individually driving light-emitting unit blocks, a backlight assembly for performing the method, and a display apparatus having the backlight assembly.
2. Discussion of Related Art
Generally, a liquid crystal display (LCD) apparatus includes an LCD panel displaying an image using the light transmissivity of liquid crystals and a backlight assembly arranged under the LCD panel and supplying light to the LCD panel.
The LCD panel includes an array substrate having pixel electrodes and thin-film transistors (TFTs) electrically connected to the pixel electrodes, a color filter substrate having a common electrode and color filters, and a liquid crystal layer disposed between the array substrate and the color filter substrate.
The arrangement of the crystals of the liquid crystal layer is changed by an electric field formed between the pixel electrodes and the common electrode, so that the light transmissivity of the liquid crystal layer is changed. When the light transmissivity is increased to a maximum level, the LCD panel may display a white image having the highest luminance level. Whereas, when the light transmissivity is decreased to a minimum level, the LCD panel may display a black image having the lowest luminance level.
Because the liquid crystal layer is generally difficult to perfectly arrange in a definite direction, however, the LCD panel may generate light leakage at low grayscale values. That is, it may be difficult for the LCD panel to display a perfectly black image, so that the LCD panel may display an image having a low contrast ratio.
In order to prevent a contrast ratio of the image from decreasing, a local dimming method capable of individually generating light according to a position on the panel was recently developed. The local dimming method is a driving method of light-emitting unit blocks that supplies dimmed light to a pixel displaying a black image of a low grayscale level for increasing the contrast ratio.